template<class BidIt>
bool next_permutation(BidIt first, BidIt last);
template<class BidIt, class Pred>
bool next_permutation(BidIt first, BidIt last, Pred pr);The first template function determines a repeating sequence of permutations, whose initial permutation occurs when the
sequence designated by iterators in the range [first, last) is ordered by operator<. (The elements are sorted in
ascending order.) It then reorders the elements in the sequence, by evaluating swap(X, Y) for the elements X and Y
zero or more times, to form the next permutation. The function returns true only if the resulting sequence is not the initial
permutation. Otherwise, the resultant sequence is the one next larger lexicographically than the original sequence. No
two elements may have equivalent ordering.
The function evaluates swap(X, Y) at most (last - first) / 2 times.
The second template function behaves the same, except that it replaces operator<(X, Y) with pr(X, Y).
Sample programs: next_permutation and next_permutation (predicate version).